Aqueous polyurethane dispersions useful for preparing polymers with improved moisture resistance properties

ABSTRACT

The present invention is a polyurethane dispersion that can be used to prepare polyurethane polymers which have moisture resistant properties. Moisture resistant polymers of the present invention are obtained by preparing the polymers from a polyurethane dispersion using a prepolymer formulation which includes an aliphatic mono, di or polyhydroxy compound which has an aliphatic side chain substituent which contains from 5 to 30 carbon atoms.

CROSS REFERENCE STATEMENT

This application claims the benefit from U.S. Provisional ApplicationNo.60/112702 filed Dec. 18, 1998.

BACKGROUND OF THE INVENTION

This invention relates to polyurethane polymers. This inventionparticularly relates to polyurethane polymers obtained from aqueouspolyurethane dispersions.

Polyurethane dispersions are known, and can be used to obtainpolyurethane polymers that can themselves be useful in variousapplications. Polyurethane/urea dispersion s can be used to obtain, forexample: carpet backings; coatings for wood finishing; glass fibersizing; textiles; adhesives; automotive topcoats and primers; films forpackaging; gloves, and other applications. Polyurethane dispersions canbe prepared by various processes, including, for example, thosedescribed in: U.S. Pat. No. 4,857,565; U.S. Pat. No. 4,742,095; U.S.Pat. No. 4,879,322; U.S. Pat. No. 3,437,624; U.S. Pat. No. 5,037,864;U.S. Pat. No. 5,221,710; U.S. Pat. No. 4,237,264; and, U.S. Pat. No.4,092,286.

Polyurethane dispersions can be obtained according to a process that isdescribed in U.S. application Ser. No. 09/039978. Dispersions preparedaccording to the process described therein can be useful for obtainingpolyurethane carpet backings and polyurethane textile backings. Problemscan result, however, in the event that a spill occurs wherein a liquidcan flow onto, or be absorbed by, the backing on the underside of acarpet. Spilled liquids such as water, urine, beverage drinks, food,blood, and feces can penetrate a carpet backing to the underside of thecarpet, which can be inaccessible to various cleaning methods. Polymericmaterials having moisture resistance can be useful in protective wearsuch as gloves, for example, or packaging.

Various conventional methods can provide a moisture barrier to polymersobtained from aqueous polymeric dispersions. For example, increasedcoating weights of a dispersion can be used, thereby increasing thethickness of the polymer. Alternatively, wax added to an aqueouspolymeric dispersion can provide a moisture barrier to carpet. Anotherknown method for providing a moisture barrier is to decrease the amountof filler used in a carpet backing formulation. A non-permeable fabricor film can also be applied to a carpet backing, as described in U.S.Pat. No. 5,763,040. Still another method involves applying afluorochemical on the underside of a secondary backing, and is describedin U.S. Pat. No. 5,348,785. Use of fluorochemicals to impart waterimpermeability is also described in U.S. Pat. Nos. 4,619,853 and4,643,930. A water-impervious film is described in U.S. Pat. No.4,336,089. Application of various hydrophobic compositions to asecondary backing is described in U.S. Pat. No. 5,558,916.

It would be desirable in the art of preparing polyurethane polymers, toprepare a polyurethane dispersion that includes a component that impartsa moisture barrier to a polyurethane polymer, without adding complexityto a manufacturing process, or significantly changing the otherproperties of the polyurethane polymer. It would also be desirable inthe art to prepare such a polymer by a process that would notsignificantly increase the cost of manufacture of the polymer, orarticles produced therefrom.

SUMMARY OF THE INVENTION

In one aspect, the present invention is an aqueous polyurethanedispersion comprising an isocyanate terminated prepolymer prepared froma formulation including a polyisocyanate and a polyol mixture, whereinthe polyol mixture includes at least one aliphatic mono, di orpolyhydroxy compound which has an aliphatic side chain substituent whichcontains from 5 to 30 carbon atoms and wherein the aliphatic mono, di orpolyhydroxy compound which has an aliphatic side chain substituent ispresent at a concentration of from 0.5 to 10 weight percent of thepolymer.

In another aspect, the present invention is a moisture resistantpolyurethane polymer comprising a polymer layer prepared by applying alayer of an aqueous polyurethane dispersion comprising an isocyanateterminated prepolymer prepared from a formulation including apolyisocyanate and a polyol mixture, wherein the polyol mixture includesat least one aliphatic mono, di or polyhydroxy compound which has analiphatic side chain substituent which contains from 5 to 30 carbonatoms and wherein the aliphatic mono, di or polyhydroxy compound whichhas an aliphatic side chain substituent is present at a concentration offrom 0.5 to 10 weight percent of the polymer to a substrate and allowingthe dispersion to cure.

In still another aspect, the present invention is a moisture resistanttextile comprising a textile and adherent thereto a polymer prepared byapplying a layer of an aqueous polyurethane dispersion comprising anisocyanate terminated prepolymer prepared from a formulation including apolyisocyanate and a polyol mixture, wherein the polyol mixture includesat least one aliphatic mono, di or polyhydroxy compound which has analiphatic side chain substituent which contains from 5 to 30 carbonatoms and wherein the aliphatic mono, di or polyhydroxy compound whichhas an aliphatic side chain substituent is present at a concentration offrom 0.5 to 10 weight percent of the polymer to the textile and allowingthe dispersion to cure.

Moisture resistant polyurethane of the present invention can be usefulin cushioned flooring applications such as attached cushion broadloom,carpet tiles, carpet underlay, or vinyl flooring; adhesivesapplications; coatings; protective clothing or protective gear such asgloves and aprons; packaging; or any application where moistureresistant polymers can be useful.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In one embodiment, the present invention is an aqueous polyurethanedispersion composition that can yield a coating or a foam having goodmoisture resistance. A polyurethane dispersion of the present inventionincludes water, and either: a polyurethane; a mixture capable of forminga polyurethane; or a mixture of both. A polyurethane dispersion of thepresent invention can optionally include: chain extenders; surfactants;fillers; dispersants; foam stabilizers; thickeners; fire retardants,and/or other optional materials that can be useful in a polyurethaneformulation.

The polyisocyanate component of the formulations of the presentinvention can be prepared using any organic polyisocyanates, modifiedpolyisocyanates, isocyanate-based prepolymers, and mixtures thereof.These can include aliphatic and cycloaliphatic isocyanates, but aromaticand especially multifunctional aromatic isocyanates such as 2,4- and2,6-toluenediisocyanate and the corresponding isomeric mixtures;4,4′-,2,4′- and 2,2′-diphenyl-methanediisocyanate (MDI) and thecorresponding isomeric mixtures; mixtures of 4,4′-, 2,4′- and 2,2′-diphenylmethanediisocyanates and polyphenyl polymethylenepolyisocyanates PMDI; and mixtures of PMDI and toluene diisocyanates arepreferred. Most preferably, the polyisocyanate used to prepare theprepolymer formulation of the present invention is MDI or PMDI.

A polyurethane dispersion of the present invention is an aqueousdispersion of a polyurethane and/or polyurethane-forming materials. Forthe purposes of the present invention, polyurethane dispersions caninclude other polymeric and/or oligomeric compounds including, but notlimited to: ureas, biurets, allophonates, and other compounds havingfunctionality that can be derived from the reaction of an isocyanatewith the various active hydrogen containing compounds present in theformulation. Polyurethane-forming materials, as the term is used in thepresent invention, are materials which are capable of formingpolyurethane polymers. Polyurethane-forming materials include, forexample, polyurethane prepolymers. Prepolymers useful in the practice ofthe present invention can be prepared by reacting activehydrogen-containing compounds with an amount of isocyanate in excess ofthe active hydrogen functionality present in the reaction mixture. Theisocyanate functionality can be present in an amount of from about 0.2wt. percent to about 40 wt. percent of the dispersion. A suitableprepolymer can have a molecular weight in the range of from about 100 toabout 10,000.

Prepolymers useful in the practice of the present invention should besubstantially liquid under the conditions of dispersal. While it ispossible to add a liquid solvent or diluent such as a volatile organiccompound (VOC) to the prepolymer to obtain a more fluid prepolymer, itis preferred in this invention to utilize no solvent or diluent, as theremoval of these ingredients require extra processing steps and possibleenvironmental consequences from the use of these VOCs. Preferably, thepolyurethane dispersions of the present invention are prepared in thesubstantial absence of an organic solvent.

Active hydrogen compounds are compounds having functional groups thatcontain at least one hydrogen atom bonded directly to an electronegativeatom such as nitrogen, oxygen or sulfur. Various types of activehydrogen compounds, such as amines, alcohols, polyether polyols,polyester polyols, and mercaptans, for example, are known to thoseskilled in the art of preparing polyurethane polymers. Active hydrogencompounds suitable for use in the practice of the present invention canbe polyols having molecular weights of less than about 10,000.

The aliphatic substituted hydroxy functional compound employed in theinvention can consist of any compound possessing an aliphaticsubstituent of from 1 to 30 carbon atoms and one or more hydroxylgroups. Examples of such compounds include glycols such as glycerin,trimethylolpropane, or trimethylolethane which are partially esterifiedwith a 1 to 30 carbon carboxylic acid, preferably a 5 to 22 carboncarboxylic acid, and more preferably a 10 to 15 carbon carboxylic acid.Examples of these compounds include the group consisting of glycerolmonooleate, glycerol monobehenate, glycerol monotallate, glycerolmonostearate, glycerol monopalmitate, trimethylolpropane monostearate,and mixtures thereof. Other types of compounds include polymericversions of the aforementioned compounds, and copolymers of thesecompounds with other glycols, diols and acids or anhydrides. Inaddition, the aliphatic substituent may be attached to the hydroxylportion of the compound via heteroatoms such as oxygen or nitrogen, suchcompounds include the N,N-bis(hydroxyalkyl) alkylamines, one example ofwhich is N-stearyl diethanolamine. Branched chain hydroxy alkanes suchas 1,2-dihydroxyoctadecane may also be used. Additionally sorbitan basedesters such as the group consisting of sorbitan monostearate, sorbitanmonooleate, sorbitan monolaurate, sorbitan monooleate, and mixturesthereof may also be used. Of these, the glycerol monoesters arepreferred.

The aliphatic substituted hydroxy functional compound employed in thepresent invention can be used in a suprizingly low concentration toprepare polymers which are effective at repelling moisture. Preferably,the aliphatic substituted hydroxy functional compounds are present at aconcentration of from 0.5 to 10 percent of the polymer weight of apolyurethane dispersion. More preferably, the aliphatic substitutedhydroxy functional compounds are present at a concentration of from 1.0to 4.5 percent of the polymer weight of a polyurethane dispersion andeven more preferably, the aliphatic substituted hydroxy functionalcompounds are present at a concentration of from 1.5 to 2.5 percent ofthe polymer weight of a polyurethane dispersion.

Other types of aqueous polymeric dispersions can be used in combinationwith the polyurethane dispersions of the present invention. Suitabledispersions useful for blending with polyurethane dispersions of thepresent invention include: styrene-butadiene dispersions;styrene-butadiene-vinylidene chloride dispersions; styrene-alkylacrylate dispersions; or acrylic dispersions; like compounds andmixtures thereof.

The present invention optionally includes a chain extender or acrosslinker. A chain extender is used herein to build the molecularweight of the polyurethane prepolymer by reaction of the chain extenderwith the isocyanate functionality in the polyurethane prepolymer, i.e.,chain extend the polyurethane prepolymer. A suitable chain extender orcrosslinker is typically a low equivalent weight active hydrogencontaining compound having about 2 or more active hydrogen groups permolecule. Chain extenders typically have 2 or more active hydrogengroups while crosslinkers have 3 or more active hydrogen groups. Theactive hydrogen groups can be hydroxyl, mercaptyl, or amino groups. Anamine chain extender can be blocked, encapsulated, or otherwise renderedless reactive. Other materials, particularly water, can function toextend chain length and, therefore, can be chain extenders for purposesof the present invention.

Polyamines are preferred chain extenders. It is particularly preferredthat the chain extender be selected from the group consisting of amineterminated polyethers such as, for example, Jeffamine D-400 fromHuntsman Chemical Company, amino ethyl piperazine, 2-methyl piperazine,1,5-diamino-3-methyl-pentane, isophorone diamine, ethylene diamine,diethylene triamine, aminoethyl ethanolamine, triethylene tetraamine,triethylene pentaamine, ethanol amine, lysine in any of itsstereoisomeric forrns and salts thereof, hexane diamine, hydrazine andpiperazine. In the practice of the present invention, the chain extendercan be used as an aqueous solution.

While optional, in preparing a polyurethane polymer of the presentinvention use of a chain extender can be advantageous. Generally, achain extender is employed in an amount sufficient to react with fromabout zero (0) to about 100 percent of the isocyanate functionalitypresent in the prepolymer, based on one equivalent of isocyanatereacting with one equivalent of chain extender. It can be desirable toallow water to act as a chain extender and react with some or all of theisocyanate functionality present. A catalyst can optionally be used topromote the reaction between a chain extender and an isocyanate.

Catalysts are optional in the practice of the present invention.Catalysts suitable for use in the present invention include tertiaryamines, and organometallic compounds, like compounds and mixturesthereof. For example, suitable catalysts include di-n-butyl tinbis(mercaptoacetic acid isooctyl ester), dimethyltin dilaurate,dibutyltin dilaurate, dibutyltin sulfide, stannous octoate, leadoctoate, ferric acetylacetonate, bismuth carboxylates,triethylenediamine, N-methyl morpholine, like compounds and mixturesthereof. An amount of catalyst is advantageously employed such that arelatively rapid cure to a tack-free state can be obtained. If anorganometallic catalyst is employed, such a cure can be obtained usingfrom about 0.01 to about 0.5 parts per 100 parts of thepolyurethane-forming composition, by weight. If a tertiary aminecatalyst is employed, the catalyst preferably provides a suitable cureusing from about 0.01 to about 3 parts of tertiary amine catalyst per100 parts of the polyurethane-forming composition, by weight. Both anamine type catalyst and an organometallic catalyst can be employed incombination.

The present invention optionally includes a filler material. The fillermaterial can include conventional fillers such as milled glass, calciumcarbonate, aluminum trihydrate, talc, bentonite, antimony trioxide,kaolin, fly ash, or other known fillers. In the practice of the presentinvention, a suitable filler loading in a polyurethane dispersion can befrom about 100 to about 1000 parts of filler per 100 parts ofpolyurethane. Preferably, filler can be loaded in an amount of at leastabout 200 pph, more preferably at least about 300 pph, most preferablyat least about 400 pph.

The present invention optionally includes a filler wetting agent. Afiller wetting agent generally can help make the filler and thepolyurethane-forming composition compatible with one another. Usefulwetting agents include phosphate salts such as sodium hexametaphosphate.A filler wetting agent can be included in a polyurethane-formingcomposition of the present invention at a concentration of at leastabout 0.5 parts per 100 parts of filler, by weight.

The present invention optionally includes thickeners. Thickeners can beuseful in the present invention to increase the viscosity of lowviscosity polyurethane dispersions. Thickeners suitable for use in thepractice of the present invention can be any thickener known in the artof preparing polyurethane dispersions. For example, suitable thickenersinclude ALCOGUM VEP-II*(*ALCOGUM™ VEP-II is a trade designation of AlcoChemical Corporation) and PARAGUM 231*(*PARAGUM 231 is a tradedesignation of Para-Chem Southern, Inc.). Thickeners can be used in anyamount necessary to obtain a dispersion of desired viscosity.

The present invention can include other optional components. Forexample, a polyurethane-forming composition of the present invention caninclude surfactants, blowing agents, frothing agents, fire retardant,pigments, antistatic agents, reinforcing fibers, antioxidants,preservatives, acid scavengers, and the like. Examples of suitableblowing agents include: gases and/or mixtures of gases such as, forexample, air, carbon dioxide, nitrogen, argon, helium, and the like;liquids such as, for example, water, volatile halogenated alkanes suchas the various chlorfluoromethanes and chlorfluoroethanes; azo-blowingagents such as azobis(formamide).

Frothing agents are typically introduced by mechanical introduction of agas into a liquid to form a froth (mechanical frothing). Mechanicalfrothing of a polyurethane polymer is a procedure known and practice bythose skilled in the art of preparing polyurethane polymers. Inpreparing a frothed polyurethane foam, it is preferred to mix allcomponents and then blend the gas into the mixture, using equipment suchas an Oakes or Firestone foamer. In the preparation of a froth for acarpet backing, it is not necessary to obtain a froth that is stable. Ina carpet backing production process, a frothed foam typically is spreadon the back of a carpet using a spreading tool, which destroys the frothin the process.

Surfactants are optional, but can be desirable in the practice of thepresent invention. Surfactants useful herein can be cationicsurfactants, anionic surfactants, or a non-ionic surfactants. Examplesof anionic surfactants include sulfonates, carboxylates, and phosphates.Examples of cationic surfactants include quaternary amines. Examples ofnon-ionic surfactants include block copolymers containing ethylene oxideand silicone surfactants. Surfactants useful in the practice of thepresent invention can be either external surfactants or internalsurfactants. External surfactants are surfactants which do notchemically react with the polymer to form a covalent bond during thepreparation of the dispersion. Internal surfactants are surfactantswhich do become chemically reacted into the polymer during dispersionpreparation. A surfactant can be included in a formulation of thepresent invention in an amount ranging from about 0.01 to about 20 partsper 100 parts by weight of polyurethane component. Preferabley, theformualtions of the present invention include polyurethane prepolymerswhich are not internal surfactants.

Generally, any method known to one skilled in the art of preparingpolyurethane dispersions can be used in the practice of the presentinvention to prepare a moisture resistant polymer of the presentinvention. A moisture resistant polymer of the present invention can beprepared from polyurethane dispersions that are storage-stable orpolyurethane dispersions that are not storage-stable. A storage-stablepolyurethane dispersion as described herein is any polyurethanedispersion having a mean particle size of less than about 5 microns. Apolyurethane dispersion that is not storage-stable can have a meanparticle size of greater than 5 microns. For example, a suitabledispersion can be prepared by mixing a polyurethane prepolymer withwater and dispersing the prepolymer in the water using a commercialblender. Alternatively, a suitable dispersion can be prepared by feedinga prepolymer into a static mixing device along with water, anddispersing the water and prepolymer in the static mixer. Continuousmethods for preparing aqueous dispersions of polyurethane are known andcan be used in the practice of the present invention. For example, U.S.Pat. Nos.: 4,857,565; 4,742,095; 4,879,322; 3,437,624; 5,037,864;5,221,710; 4,237,264; and 4,092,286 all describe continuous processesuseful for obtaining polyurethane dispersions. In addition, apolyurethane dispersion having a high internal phase ratio can beprepared by a continuous process as described in U.S. Pat. No.5,539,021, incorporated herein by reference. In addition, it can beadvantageous to combine a continuous process for preparing a prepolymerwith a continuous feed dispersion process in order to maximize processefficiency as discussed in pending U.S. application Ser. No. 09/039978.

The polymers of the present invention can be applied to any substrate,but preferably the substrate is a textile. More preferably, thesubstrate is a carpet and the polymer is in the form of a moistureresistant backing. A carpet backing of the present invention can beprepared from a polyurethane dispersion of the present invention,described hereinabove, using either conventional or non-conventionalmethods in the art of preparing polyurethane-backed carpets. Inpreparing polyurethane-backed carpets of the present invention, apolyurethane-forming composition can be applied as a layer of preferablyuniform thickness onto one surface of a carpet substrate. Polyurethanedispersions of the present invention can be applied as a precoat,laminate coat or as a foam coat. Polyurethane precoats, laminate coats,and foam coats can be prepared by methods known in the art. Precoats,laminate coats and foam coats prepared from dispersions are described inP. L. Fitzgerald, “Integral Latex Foam Carpet Cushioning”, Coat. Fab.1977, Vol. 7 (pp.107-120), and in R. P. Brentin, “Latex Coating Systemsor Carpet Backing”, J. Coat. Fab. 1982, Vol. 12 (pp. 82-91), forexample.

A polyurethane-forming composition can be applied to one surface of acarpet ubstrate before it cures to a tack-free state. Alternatively, apolyurethane dispersion containing completely reacted isocyanatefunctionality can be applied to a suitable substrate, thereby removingthe need to cure the polymer. Typically the polyurethane-formingcomposition is applied to the surface that is attached to a primarybacking but can be applied to a secondary backing such as mesh orfleece. The composition can be applied using equipment such as a doctorknife, air knife, or extruder to apply and gauge the layer.Alternatively, the composition may be formed into a layer on a movingbelt or other suitable apparatus and dehydrated and/or partially cured,then married to the carpet substrate using equipment such as a doublebelt (also known as double band) laminator or a moving belt with anapplied foam cushion. The amount of polyurethane-forming compositionused can vary widely, from about 5 to about 500 ounces per square yard,depending on the characteristics of the textile. After the layer isapplied and gauged, water is removed from the dispersion and the layercan be cured using heat from any suitable heat source such as aninfrared oven, a convection oven, or heating plates.

In the practice of the present invention, any of the steps used inpreparing a polyurethane carpet backing can be carried out in acontinuous manner. For example, in a first step the prepolymer can beprepared from a suitable active hydrogen containing compound in acontinuous manner; the prepolymer can be fed, as it is obtained in thefirst step, into a mixing device with water to obtain an aqueousdispersion; the aqueous dispersion can be applied to a carpet substratein a continuous manner to obtain a polyurethane backed carpet.

The following example is provided to illustrate the present invention.The example is not intended to limit the scope of the present inventionand should not be so interpreted.

EXAMPLE 1

A prepolymer, hereinafter Prepolymer A, is prepared as follows:

195.7 parts (0.1957 eq.) of VORANOL 5287*, a 12.5 percent ethylene oxidecapped polypropylene oxide diol with an equivalent weight of 1000 g/eq;93.02 parts (0.7442 eq.) of ISONATE 25OP*, a mixture of 25 percent2,4′-MDI and 75 percent 4,4′-MDI; 5.28 parts (0.02966 eq.) of EMEREST2421* glycerol monooleate and 6.0 parts (6.316 meq) of polyethyleneglycol monol (MPEG) having a molecular weight of 950 are mixed withheating to 70° C. in a glass vessel for about 15 hours. The resultantprepolymer has a percent NCO of 6.88, an isocyanate eqivalent weight of610, and a viscosity of 6040 cps @25 C. (EMEREST 242 is a tradedesignation of the Henkel Corp; VORANOL 5287 and ISONATE 25OP is a tradedesignation of The Dow Chemical Company).

A polyurethane dispersion is prepared as follows:

75.58 parts of Prepolymer A; 9.9 part of a DESULF DBS-25T*, a 25 percentaqueous solution of a triethanolamine salt of dodecyl benzene sulfonicacid; and 20.08 parts of water are mixed at room temperature and thenstirred at 3000 rpm in a glass flask. 44.4 parts of a10 percent aqueouspiperazine solution is added to the mixture, and stirring is continuedfor 1 minute at 3000 rpm. The resulting mixture is then stirredovernight with a stir bar and is filtered through a paint filter toyield a low viscosity, 55 percent solids polyurethane dispersion with amean particle size of 0.24 microns. (*DESULF DBS-25T is a tradedesignation of DeForest Chemical Co.)

A carpet backed with the polyurethane dispersion is prepared as follows:

The dispersion is compounded by admixing 178.6 parts of the dispersion(100 parts solids) and 200 parts calcium carbonate filler. Then, 3.0parts of PARAGUM 241* thickener is admixed. The compound is applied tothe back of a nylon level loop style carpet with a greige weight of 23oz/yd² (0.8 kg/m² ) at a coating weight of 38.5 oz/yd² (1.3 kg/M²). Apolypropylene scrim, 3.3 oz/yd² (0.11 kg/m²), is applied as a secondarybacking. The carpet is dried at 132° C. for 12 minutes, then allowed toequilibrate overnight before testing. (*PARAGUM 241 is a tradedesignation of Para-Chem Southern, Inc.)

The carpet is tested as follows:

The carpet of Example 1 has a tuftlock of 17.4 pounds (7.9 kg) , and arewet tuftlock of 11.2 pounds (5.1 kg). Tuftbind values are obtainedaccording to ASTM D1335. The carpet of Example 1 has a dry delaminationof 10.1 pounds/in. (1.8 kg/cm) and a re-wet delamination of 5.0pounds/in 0.89 kg/cm). The delamination is the strength required toremove the secondary polypropylene scrim from the fabricated carpet. Itis determined by cutting a 3 inch by 9 inch (7.6 cm×22.9 cm) strip ofcarpet, and peeling the secondary scrim from the main portion of thecarpet while measuring the force required. The rewet delamination isdetermined in the same manner, except that the carpet specimen is soakedfor one minute in water, and blotted dry prior to testing. The carpethas a hand punch of 17.7 pounds (8.0 kg). The hand punch is measured asthe force required to push a 9 inch by 9 inch (22.9cm×22.9 cm) piece ofcarpet 0.5 inches (1.27 cm) into a 5.5 inch (14 cm) inner diametercylinder at a rate of 12.0 inches (30.5 cm) per minute, using a 2.25inch (5.7 cm) outer diameter solid cylinder attached to a load cell. Thecarpet passes a water resistance test known as the British spill test inwhich 100 ml of a solution of methylene blue dye in water is poured froma height of 1 meter onto a 12×12 inch (30.5 cm×30.5 cm) piece of carpetand allowed to stand for 4 hours. The sample is inscribed with a razorknife to reveal the interior. A pass rating is given if no blue dye isfound to have penetrated into or through the backing.

EXAMPLE 2

A prepolymer and dispersion are prepared as in Example 1. The procedureof Example 1 is used to compound the dispersion, except that 100 partsof calcium carbonate, 100 parts of Gamma Sperse CS-11*, and 0.6 parts ofPARAGUM 241 are used to compound the dispersion. The compound is appliedto the back of a carpet at a coat weight of 37.1 oz/yd² (1.26 kg/m²) andthe resulting carpet gave the following test results:

Hand (lb.) 13.8 (6.3 kg) Tuftlock (lb.) 19.8 (9.0 kg) Rewet Tuftlock(lb.) 13.3 (6.0 kg) British Spill Test pass (* Gamma Sperse CS-11 is acalcium carbonate which has been treated with ammonium stearate toprovide improved hydrophobic properties and is a trade designation ofGeorgia Marble Co.)

COMPARATIVE EXAMPLE 3

Prepolymer B is prepared as follows:

190.85 parts (0.1908 eq.) of VORANOL 5287; 99.25 parts (0.794 eq.) ofISONATE 25OP*, a mixture of 25 percent 2,4′-MDI and 75 percent 4,4′-MDI; 3.9 parts (0.07358 eq.) of diethylene glycol; and 6.0 parts(6.316 meq) of polyethylene glycol monol (MPEG) having a molecularweight of 950 are mixed with heating to 70° C. in a glass vessel forabout 15 hours. The prepolymer has a percent NCO of about 7.3, anisocyanate equivalent weight of about 575, and a viscosity of about 7000cps @25 C. (*ISONATE 25OP is a trade designation of The Dow ChemicalCompany).

A polyurethane dispersion is prepared as follows:

75.5 parts of Prepolymer B; 9.9 parts of a 25 percent aqueous solutionof the triethanolamine salt of dodecyl benzene sulfonic acid; and 19.3parts of water are mixed at room temperature and then stirred at 3000rpm in a glass flask. 45.3 parts of a 10 percent aqueous piperazinesolution is added to the mixture, and stirring is continued for 1 minuteat 3000 rpm. The resulting mixture is stirred overnight with a stir barand filtered through a paint filter to yield a low viscosity, 55 percentsolids polyurethane dispersion with a mean particle size of 0.3 microns.

A Carpet backed with the polyurethane dispersion is prepared as follows:

The dispersion is compounded by admixing 178.6 parts dispersion (100parts solids) with 200 parts calcium carbonate filler. 4.1 parts ofPARAGUM 241 is then admixed. The compound is applied to the back of anylon level loop style carpet with a greige weight of 23 oz/yd² (0.8kg/m²) at a coating weight of 38.5 oz/yd² (1.3 kg/m ). A polypropylenescrim, 3.3 oz/yd² (0.11 kg/m²), is applied as a secondary backing. Thecarpet is dried at 132° C. for 12 minutes, then allowed to equilibrateovernight before testing.

The carpet is tested as follows:

The carpet of Comparative Example 3 is tested substantially identicallyto the carpet of Example 1. It has a tuftlock of 18.5 pounds (8.4 kg),and a rewet tuftlock of 8.9 pounds (4.0 kg). The carpet of ComparativeExample 3 has a dry delamination of 10.1 pounds/in. (1.8 kg/cm) and arewet delamination of 5.0 pounds/in. (0.89 kg/cm). The carpet ofComparative Example 3 has a hand punch of 14.7 pounds (6.7 kg). Thecarpet failed the British spill test.

COMPARATIVE EXAMPLE 4

A prepolymer and dispersion are prepared as in Comparative Example 3.The procedure of Comparative Example 3 is used to compound thedispersion, except that 100 parts of calcium carbonate, 100 parts ofGAMMA SPERSE CS-11, and 0.98 parts of PARAGUM 241 are used to compoundthe dispersion. The compound is applied to the back of a carpet at acoat weight of 38.5 (1.3 kg/m²)oz/yd², and the resulting carpet gave thefollowing test results:

Hand (lb.) 11.8 (5.4 kg) Tuftlock (lb.) 18.9 (8.6 kg) Rewet Tuftlock(lb.) 12.4 (5.6 kg) British Spill Test fail

What is claimed is:
 1. A moisture-resistant textile comprising: amoisture-resistant polyurethane polymer affixed to a substrate, (a) saidsubstrate being a textile; and (b) said moisture-resistant polyurethanepolymer being prepared from an aqueous polyurethane dispersioncomprising an isocyanate-terminated prepolymer and an externalsurfactant, said prepolymer being prepared from a polyisocyanate and apolyol mixture and said polyol mixture comprising at least one glycerolmonoester, said glycerol monoester being present in a concentration offrom 0.5 to 10 weight percent of said polymer.
 2. The moisture resistanttextile of claim 1 wherein the textile is a carpet.
 3. The moistureresistant textile of claim 2 wherein the textile passes the BritishSpill Test.
 4. The moisture-resistant textile according to claim 1,wherein said polyisocyanate comprises MDI.
 5. The moisture-resistanttextile according to claim 1, wherein said glycerol monoester comprisesat least one of glycerol monooleate, glycerol monobehenate, glycerolmonotallate, glycerol monostearate, glycerol monopalmitate, andtrimethylolpropane monostearate.
 6. The moisture-resistant textileaccording to claim 1, wherein said glycerol monoester is present in aconcentration of from 1.0 to 4.5 weight percent of said polymer.
 7. Themoisture-resistant textile according to claim 1, wherein said glycerolmonoester is present in a concentration of from 1.5 to 2.5 weightpercent of said polymer.
 8. The moisture-resistant textile according toclaim 1, wherein said external surfactant comprises an anionicsurfactant.
 9. The moisture-resistant textile according to claim 1,wherein said external surfactant comprises a triethanolamine salt ofdodecyl benzene sulfonic acid.
 10. The moisture-resistant textileaccording to claim 1, wherein said polyol mixture further comprises apolyether polyol.
 11. The moisture-resistant textile according to claim1, wherein said dispersion is prepared in the substantial absence oforganic solvent.
 12. The moisture-resistant textile according to claim1, wherein said dispersion further comprises a filler.
 13. Themoisture-resistant textile according to claim 12, wherein said fillercomprises at least one of milled glass, calcium carbonate, aluminumtrihydrate, talc, bentonite, antimony trioxide, kaolin, and fly ash. 14.The moisture-resistant textile according to claim 13, wherein saidfiller comprises calcium carbonate.